N-cycloalkyl hydroxamic acids

ABSTRACT

WHEREIN N IS AN INTEGER OF FROM 3 TO 6, INCLUSIVE, AND R is a hydrocarbon radical containing from 1 to 20 carbon atoms. A new class of compounds useful, for example, as metal extractants, is provided. The compounds are hydroxamic acids, with N-cycloalkyl groups and represented by the general formula:   D R A W I N G

United States Patent Chappelow, Jr. et al.

[451 Aug. 19, 1975 Assignee:

Filed:

Engel, both of Kansas City, Mo.

Kerr-McGee Corporation,

Oklahoma City, Okla.

Oct. 29, 1973 Appl. No.: 410,954

Related US. Application Data [62] Division of Ser. No. 149,750. June 3, 1971, Pat. No.

[52] U.S. C1. 260/5005 1H [51] Int. Cl. C07C 119/00; C07C 103/75 [58] Field of Search 260/5005 H [56] References Cited UNITED STATES PATENTS 3,277,107 10/1966 Neighbors 260/5005 H 3,282,986 11/1966 Kaczka 260/5005 H 3,439,018 4/1969 Brookes et a1 260/5005 H 3,464,784 9/1969 Swanson 260/5005 H 3,691,234 9/1972 Kiefer 260/5005 H OTHER PUBLICATIONS Gupta et al., .1. lnorg. Nucl. Chem., 1972, Vol. 34, pp. 350-352.

Primary Exuminer-Joseph E. Evans Attorney, Agent, or FirmWilliam G. Addison 5 7 ABSTRACT A new class of compounds useful, for example, as metal extractants, is provided. The compounds are hydroxamic acids, with N-cycloalkyl groups and represented by the general formula:

l |-1 n-t z-n-ca- (ca cs wherein n is an integer of from 3 to 6, inclusive, and R is a hydrocarbon radical containing from 1 to 20 carbon atoms.

6 Claims, N0 Drawings N-CYCLOALKYL HYDROXAMIC ACIDS This is a division of co-pending application Ser. No. 149,750 filed June 3, 1971 now U.S. Pat. No. 3,825,585.

BACKGROUND OF THE INVENTION Certain organic compounds are known to have the ability to chelate metal ions. Thus, it is known that the compound N-phenylbenzohydroxamic acid has been used for many years as a pentavalent vanadium extractant in analytical procedures. However, there is a need for additional compounds having the capability of functioning as selective extractants for various metal ions in commercial metallurgical operations.

DESCRIPTION OF A PREFERRED EMBODIMENT This invention relates to certain novel N-substituted hydroxamic acids. The N-substituted hydroxamic acids of the invention have cycloalkyl groups and are capable of chelating metal ions.

The novel compounds of the present invention are represented by the general formula:

- CH (CH2) CH2 wherein R is selected from the group consisting of alkyl, cycloalkyl, alkaryl, substituted alkaryl, aralkyl, substituted aralkyl, heterocyclic, substituted heterocyclic, aryl, substituted aryl, alkoxyaryl, or substituted alkoxyaryl radicals having from 1 to 20 carbon atoms and n is an integer of from 3 to 6, inclusive. Obviously when R contains an aryl group it must contain at least 6 carbon atoms. Thus, when R contains an aryl group, it will have from 6 to 20 carbon atoms. A preferred group of radicals are those containing from 6 to 16 carbon atoms.

Examples of the group CH (CH cs include cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

Examples of the radical R include heptyl, octyl, decyl, octadecyl, diethylheptyl, butylcyclohexyl, pethylphenyl, p-t-butylphenyl, 2-thienyl. 2-furyl, cinnamyl, 2quinolyl, p-octylphenyl, p-pentyloxyphenyl, p-octyloxyphenyl, phenylmethyl, phenoxymethyl and the like. The substituted R groups can contain as substituents halogens or nitro, alkoxy or phenoxy groups.

Representative compounds are N-cyclooctylbenzohydroxamic acid; N-cyclopentylbenzohydroxamic acid; N-cyclohexyl-p-t-butylbenzohydroxamic acid and N-cycloheptylbenzohydroxamic acid.

The compounds of this invention may be synthesized by reacting the appropriate N-cycloalkylhydroxylamine of the formula:

l l CH (ca err NHOH wherein n has a value of 3, 4, or 6. Thus, the applicable amines are N-cyclopentylhydroxylamine, N-cyclohexylhydroxylamine, N-cycloheptylhydroxylamine and N-cycl0octylhydroxylamine.

The cycloalkylhydroxylamine is reacted with an acid chloride of the following formula:

R-i-Cl l" l R E c1 cs (cacu NHOl-I-) F "l R Ii cu (Cl-1 CH2 c1 The foregoing description and the following specific examples are for the purpose of illustration and not to be considered to be limiting the scope of the invention,

reference being had to the appended claims for this purpose.

EXAMPLE A N-Cyclohexyl-p-Chlorobenzohydroxamic Acid To a stirred solution of 23.0 g. (0.2 mole) of N-cyclohexylhydroxylamine in 400 ml. of tetrahydrofuran was added dropwise 17.5 g. (0.1 mole) of p chlorobenzoyl chloride. After completion of the addition, which caused the temperature to rise from 25 to 35C., the reaction mixture was cooled to 5C. and filtered. The filtrate was evaporated to dryness and the solid residue was washed with water. The resultant solid was dissolved in hot benzene, dried over anhydrous sodium sulfate, filtered and cooled. A total of 15.4 g. (a 61% yield) of N-cyclohexyl-p-chlorobenzohydroxamic acid was obtained as a white crystalline powder, m.p. l69l7lC.

N-cyclooctylbenzohydroxamic acid and N-cycloheptylbenzohydroxamic acid were prepared in a similar manner, the respective yields being 42 and 58 percent. All of the products were characterized by elemental analysis, infrared and nuclear magnetic resonance spectroscopy. Many other compounds have been made by this method, for example, Ncyclohexyl-2- ethylhexanohydroxamic acid was made in 54 percent yield.

EXAMPLE B N-Cyclohexyl-n-octanohydroxamic Acid To a stirred solution of l 1.5 g. (0.1 mole) of N-cyclohexylhydroxylamine and 7.0 g. (0.1 mole) of pyridine in 400 ml. of diethyl ether, 16.3 g. (0.1 mole) of n-octanoyl chloride was added dropwise. During the addition, the temperature was controlled at 0C. with an ice bath surrounding the reaction vessel. The solution was filtered, the ether evaporated and the product recrystallized. The yield was 16 percent. When this compound was prepared by the method described in Example A, the yield was 70 percent. The product was characterized by the methods described in Example A.

The following series of tests were performed for the purpose of demonstrating the utility of the N- substituted cycloalkyl hydroxamic acids of the instant invention as extractants for certain metal ions.

It will be appreciated by those skilled in the art that 5 The general procedure utilized was to prepare a 0.01 the N-substituted cycloalkylhydroxamic acids of the molar synthetic acidic solution of vanadium. Substaninstant invention may be prepared by either of the protially all of the vanadium being present in either the tetcedures outlined in Examples A and B above. The perravalent state [oxovanadium(IV)] or in the pentavalent centage yield of product will, of course, depend upon oxidation state [dioxovanadium(V)] as indicated in the the procedure utilized. The procedure that will yield Table 1 below. A sufficient amount of H 80 was added the highest percentage of product will depend upon the to the solution to provide a pH of about 1.0. The soluconstituents utilized and can be readily determined tion thus prepared was contacted with an extractant with a minor amount of experimentation. comprising an N-substituted cycloalkyl hydroxamic Further, examples of the compounds that are conacid in an organic carrier. Samples of the solution were templated within the scope of the instant invention inobtained, at various time intervals, analyzed to deterclude N-cyclohexyl2-methoxybenzohydroxamic acid, mine the percent vanadium extracted utilizing the vari- N-cyclohexyl-p-methylbenzohydroxamic acid, N- ous extractants and the results recorded in Table I becyclohexyl-3-nitrobenzohydroxamic acid, N- low.

TABLE I THE EXTRACT ANT PROPERTIES OF NSUBSTITUTED HYDROXAMIC ACIDS Oxidation Molarity Percent Vanadium Extracted at Various State of the of Organic Contact Times (min.) Extructant Vanadium Extractant Carrier 5 15 I000 N-Cyclooctylbenzo- IV 0.050 Toluene 16.0 35.0 57.0 73.0 81.0 82.0

hydroxamic Acid N-Cycloheptylbenzo- IV 0.050 Toluene 37.0 68.0 78.0 82.0 82.0 82.0

hydroxamic Acid N Cyclohexyl IV 0.050 Toluene 48.0 69.0 76.0 77.0 76.0 77.0

phenylethano hydroxamic Acid NCyclohexyl-3 IV 0.025 Toluene 28.0 33.0 33.0

nitrobenzohydroxamic Acid NCyclohexyl-Z- IV 0.025 Toluene 49.0 58.0 59.0 56.0 58.0 56.0

methoxyhenzohydroxamic Acid N Cyclohexy1-n- IV 0.050 Toluene 79.0 81.0 81.0 81.0 81.0 81.0

butanohydroxamic Acid N Cycl0hexyln- IV 0.050 Toluene 62.0 83.0 850 85.0 85.0 85.0

pentanohydroxamic Acid N-Cyclohexyl-n- IV 0.050 Toluene 32.0 59.0 77.0 84.0 86.0 86.0 hexanohydroxamic 0.050 n-Hcxane 21.0 22.0 22.0 22.0 24.0 25.0 Acid I N-Cyclohexyl-n- IV 0.050 Toluene 15.0 28.0 40.0 61.0 70.0 78.0

heptanohydroxamic Acid N-Cyclohexyl-n IV 0050 Toluene 10.0 22.0 34.0 49.0 62.0 68.0

octanohydroxamic Acid N-Cyclohexylbenzo- IV 0050 Toluene 67.0 75.0 76.0 76.0 75.0 76.0 80.0 80.0

hydroxamic Acid TDA(5 78.0

IV 0050 Toluene 70.0 81.0 84.0 84.0 84.0 84.0 78.0

V 0050 Toluene 100.0

00.0 00.0 00.0 +TDA(5"/(-) V 0.050 Toluene 93.5 90.6 84.3 82,7 79.7

00.0 N-Cyclohcxyl-p- 1V 0.025 Toluene 23.0 40.0 51.0 54.0 540 54.0

methylbenzohydroxamic Acid TDA Tridccannl Alcohol cyclohexylphenylethanohydroxamic acid, N- What IS claimed is: cyclohexy1cyclohexylmethanohydroxamic acid, N l. A compound of the formula cyclohexyl-n-octanohydroxamic acid, N-cyclohexyl-nhcptanohydroxamic acid, N-cyclohexyl-n-hexanohywherein R is selected from the group consisting of alkaryl, substituted alkaryl, aralkyl, substituted aralkyl, aryl and substituted aryl, radicals the substituted radicals being substituted with a member selected from the 6 group consisting of halogen, nitro alkoxy and phenoxy, 4. A compound as set forth in claim 2 wherein n said radicals having from 6 to 20 carbon atoms and n equals 4. is an integer of from 3 to 6, inclusive- 5. A compound as set forth in claim 2 wherein n 2. A compound as set forth in claim 1 wherein R conequals 5 talus from 6 to 16 carbon atoms' 5 6. A compound as set forth in claim 2 wherein n 3. A compound as set forth in claim 2 wherein n equals 6' equals 3. 

1. A COMPOUND OF THE FORMULA
 2. A compound as set forth in claim 1 wherein R contains from 6 to 16 carbon atoms.
 3. A compound as set forth in claim 2 wherein n equals
 3. 4. A compound as set forth in claim 2 wherein n equals
 4. 5. A compound as set forth in claim 2 wherein n equals
 5. 6. A compound as set forth in claim 2 wherein n equals
 6. 